Adobe Photoshop
When I was in 9th grade, I saved all my money from delivering newspapers and I bought a Macintosh SE. I saw a comic-book called "Shatter," that was illustrated by Mike Saenz (Bert Monroy did background illustrations) using a Mac and a program called MacPaint, and I had seen the future.
The first program I bought was FullPaint, which was almost identical to MacPaint except it had full screen modes. It wasn't long after I got my Mac that I purchased Thunderscan - a scanner that worked in conjunction with the Apple ImageWriter II dot-matrix printer. It was an 8-bit grey-scale scanner, but with my modest SE, I could only do 1-bit. I still thought it was really cool to scan and manipulate photos.
It wasn't until my junior year of college that I was finally introduced to Photoshop. I was working on my BFA in photography doing all these crazy darkroom compositing and effects in an old-school way. While I liked Photoshop 2.5, but it lacked a feature we take for granted these days: Layers. I also needed a cheaper way to get images out on paper. Fortunately, Photoshop 3.0 and the very first color Epson Ink-Jet printer came out my senior year and solved these problems. I devoted my senior year of college to learning Photoshop inside and out. Ten years later, I'm still learning.
Here is a collection of information you might find useful if you are new to Photoshop or a professional user:
Twin Cities Photoshop User Group
A bi-monthly Photoshop User Group in the Twin Cities that I host.
Photoshop Tips & Tricks
Links, Books, and Tips for Adobe Photoshop.
Photoshop Scripting using JavaScript
Links, Books, Tips and Scripts for scripting Adobe Photoshop.